Electrical equalizing system.



J. S. PEGK. ELECTRICAL EQUALIZING SYSTEM.

APPLIOATIONTILED NOV. 8, 1907 Patented June 15', 1909.

VLNTOR.

WITNESSES; v

"60% LXMW A T ORA/EV [N FA c7.

PATENT OFFlQE.

JOHN S. PEOK, OF MANCHESTER, ENGLAND, ASSIHNOR TO WESTINGHOUSE ELECTRIC it MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIAv ELECTRICAL EQUALIZING SYSTEM.

Specification of Letters Fatent.

Patented June 15, 1909.

T 0 all whom it may concern:

Be it known that. I, JOHN S. PECK, a citizen of the United States, and a resident of lvlanchester, England, have invented a new and useful Improvement in Electrical EquallZlZ Systems, of which the following is a specmcation.

My invention relates to systemsof electrical distributitni, and part-icularlyto means l'or equalizing the load upon the generating or supply station when the load upon the system is variable.

The object of my invention is to provide simple and cl'l'ective means that may be employed in connection with alternating current systems of any number of phases for absorbing or yielding energy in accordance with variations in load upon the system, in such a manner that theload upon the generating or V supply station of the system may remain su stantially constant or may not exceed a predetermined value.

It has heretofore been proposed to employ l'lyavhceis, or other devices having considerable inertia, in systems of distribution that supply translating devices requiring widely varying amounts of power, and to so drive the iv-wheels. and control their operation that the load upon the distributing circuit will remain substantially constant, regardis" if the variations in the amount of power ired by the translating devices. This lli has usually been eflectcd by providing a motor-generator set between the translating devices and the distributing circuit, the lly-avlu-cl brin g coupled to the motor-generator set, and the motor beingcaused to increase its speed to store energy in the flywheel .vhen the load ail ordcd by the translating device is less than a predetermined value, while, when the current required by the translating device exceeds the predetermined amount, provision is made for adecrcaso of the motor speed, so that the flywheel yield a portion of its potential energy and assist the motor to drive the gen orator. in such systems, however, a motorgencrator set must be provided for, each translating device, or set of translating devices having similar functions, and both motor and generator must be of sutlicient' c:' .-p.-rcity to carry the maximum load provided by the translating device.

l 1 systems have been devised in which gle equalizer set need be employed when a plurality of translating devices are supplied from a distributing circuit, such systems usually comprising a rotary converter that is connected at one side to the distributing circuit and at the other side, either to a storage battery, or to a direct current dynamo-electric machinehaving a fiy-wheel mechanically coupled thereto. With the latter arrangement, the dynamo-electric machine operates as a motor when the current required of the distributing circuit is less than a predetermined amountand stores energy in the fly-Wheel, and operates as a generator when the current required of the distributing circuit is greater than the said predetermined amount, the energy reviously stored in the fly-wheel being uti ized as the actuating means for the generator.

In the present system, a dynamo-electric machine, that may operate either as a motor or as a generator and to which a fly-wheel is mechanically coupled, is directly connected to the distributing circuit without the intervention of a rotary converter or other device, and the arrangement is such that but comparatively small and inexpensive machines need be provided and only a single equalizer set is necessary for equalizing the load provided by a plurality oi translating devices.

In its most useful embodiment, the invention comprises a multiphase distributing circult, and a plurality of mechanically coupled dynamo-electric machines of the commutator type, one for each phase of the system 01" distribution, a fly-wheel being also coupled to the said machine. The armatures of the machines are connected, respectively, to the various phases of the distributing circuit, and the field magnet windings are supplied from a multi-phase generator with currents of such a phase that the generated and counter electromotive forces of the armatures are of approximately the same phases as the electromotive forces of the circuits to which they are connected. The machines are caused to l operate alternately as motors and generators by adjusting their field strengths in accordance with variations in the amount of current required of the distributing circuit, such adjustment being cheated by varying the field. strength ol' the multiphase generator from which the field magnet windings are supplied. The energy stored in the fly-wheel and in the rotatable system when. the machines are operated as motors is yielded'when the machines operate as generators and supply current to the distributing circuit.

In the single figure of the accompanying drawing, which is a diagrammatic view of a system of distribution embodying my invention, armatures 1 and 2 of two dynamo-electric machines of the commutator type of construction, that are adapted to operate either as motors or as generators, are mechanically coupled together and to a fly-wheel 3 whereby the rotatable system may be provided with considerable inertia, and are connected, respectively, between different pairs of conductors of a two-phase circuit 4-5-6-7 that is supplied from any suitable source, such as a generator 8, and that supplies current to any suitable load, such as an induction motor 9. Field magnet windings 10 and 11 of the dynamo-electric machines are supplied with exciting current, ol' substantially the same frequency as that ol' the distributing circuit l5- '-7, from a multiphase generator 12 that is driven by a synchronous motor 13 the armature of which is connected to the distributing circuit,-t- -6-7 lhe electromotive forces applied to the field magnet windings 10 and 11 by the generator 12 are substantially 90 out of phase with the electromotive forces of the circuit conductors to which the corresponding armatures are connected. Then, since the counter or generated GlGCtl'QlHOllVP forces of the armatures 1 and 2 (litter approximately 90 in phase from the electromotivc forces applied to the corresponding licld magnet windings, the electromotivcforces generated by the armatures will be of appmximately the same phases the electromotive forces of the circuits to which the armatures are connected and the counter electromotive l'orccs oi' the armatures will be substantially opposite in phase to the said circuit electromotiye l'orces. 'ihe dynamo-electric machines will, therefore, operate under the most favorable condi- 'tions as regards power factor and commutation. Field magnet windings 14 and 15, respectively, ol' the generator and the synchronous motor 13 may be supplied with exciting current from a small direct current. generator 16 that is carried by the shaft ol', or is otherwise operated by, the synchronorfi motor 13, or they may be supplied from any other suitable source.

in circuit with the field magnet winding 14 of the generator 12 is a subdivided resistance 17 and a controlling device 18 For governing the amount ot the resistance 17 that is included in the circuit of the winding 14, the said controlling device comprising a plural ity of stationary contact terminals 19 that are connected to the respective points ol subdivision ol' the resistance 17, an :uljacent stationary conducting strip 20, and a movable conducting segment 21 tha t is adapted to be moved over the. stationary contact terminals 19 and the strip 20 by means of an electromagnet having an actuating winding 22 to which current is supplied proportional in amount to that required of the distributing circuit by the load 9. In the present instance the magnet winding 22 is supplied with current proportional in amount to that which traverses the conductor 7 through a series transformer 23, but it will be understood, of course, that the winding may be connected directly in serieswith the conductor 7, or any other conductor of the distributing circuit, if desired.

If, during the operation ol the system, only a small amount of current is required of the distributing circuit by the load 9, the movable segment 21 of the controlling device 18 will be lowered so as to include a large portion, or all, of the resistance 17 in series with the field magnet winding 14 of the generator 12 which has the effect of causing a decrease in the voltages applied by the generator to the field magnet windings 10 and 11. Because of the decreased field strengths of the dynamo-electric machines, the counter elect-romotive forces in the armatures 1 and 2 become materially less than the electromotive forces of the conductors to which the armatures are connected and themachines are, therefore, caused to operate as motors, I

energy being then stored in the rotatable system, including the fly-wheel 3. When the current required of the distributing circuit exceeds a predetermined amount, the movable segment 21 is raised, and a portion, or all, of the resistance 17 is removed from the circuit of the field magnet winding 1 1. The increased lield strength in the generator 12 causes an increase in the voltage applied thereby to the field magnet windings 10 and 11 which, in turn, causes the electromotive forces generated in the armatures 1 and 2 to exceed the electromotive forces of the circuit conductors to which the armatures are connected, and the dynamo-electric machines are then operated as generators, utilizing the energy previously stored in the movable system as the actuating means.

While the invention has been shown as employed in connection with a two-phase system ol distribution, it will be readily understood that it may also be employed in connection with systems of any other number ol phases, and also that the parts may di'll'cr materially in. structure and arrange ment from what has been shown and described, without departing from its spirit.

I claim as my invention:

1. The combination with an alternating current distributing circuit, and a dynamoelectric machine having its armature connected thereto, ot a synchronously operated gencrator [or applying an elcclrimlotivc force-1o the licld magnet winding it the d llainowlccll'ic .machine of a diil'crcnt phase from that of the circuit to which the armature is connected, and'means for adjusting the field strength of the generator in accordance with variations in the amount of cur- I sponding armatures are associated, and

means for adjusting the field strength of the generator in accordance with variations in the 7 amount of current required of the distributing circuit. I

3. The combination with a polyphase alternating current distributing circuit and a plurality of mechanically coupled dynamoelectric machineshaving their respective ar' matures, associated with differently phased electromotive forces thereof, of means for applying to the field magnet windings of the machines electromotive forces that differ in phase, respectively, from those of the said circuit with which the corresponding armatures are associated, and means for effecting adjustment of the ratio of the respective electromotive forces of the said circuit and of the said armatures;

4. The combination with a polypliase alternating current distributing circuit and a plurality of mechanically coupled dynamoeleetric machines having their respective armatures associated with the differently phased electromotive forces thereof, of means for causing the machines to operate as motors when the current required from the distributing circuit is less than a predemeans for adjusting the field strengths of the machines in accordance with variations in the amount of current required of the distributing circuit.

6. The combination with a polyphase alternating current distributing circuit and a plurality of mechanically coupled dynamoelectric machines having their respective armatur'es associated with the differently phased electromotive forces thereof, of means for adjusting the field strengths of the machines to cause the same to operate as generators when the current required of the distributing circuit exceeds a predetermined amount and to operate as motors when the said current falls below the predetermined amount.

7. The combination with a polyphase alternating current distributing circuit and a plurality of mechanically coupled dynamoelectric machines having their respective armatures associated with the differently phased electromotive forces thereof, of a generator for supplying exciting current to the said machines, and means for adjusting the field strength of the generator in accordance with variations in the amount of current required of the distributing circuit.

In testimony whereof, I have hereunto subscribed my name this sixteenth day of October, 1907.

. JOHN S. PECK. Witnesses:

G. W. PINNER, W. ROBINSON. 

